bin/58756: can not remove in-filesystem WAPBL log

[martin%NetBSD.org@localhost]

>Number:         58756
>Category:       bin
>Synopsis:       can not remove in-filesystem WAPBL log
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Oct 16 17:00:00 +0000 2024
>Originator:     Martin Husemann
>Release:        NetBSD 10.99.12
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD space-truckin.duskware.de 10.99.12 NetBSD 10.99.12 (GENERIC) #371: Tue Oct 15 14:52:33 CEST 2024 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/evbarm/compile/GENERIC evbarm
Architecture: earmv7hfeb
Machine: evbarm
>Description:

I moved a filesystem from rotating disk to SSD and would like to get rid of
the WAPBL log. However, tunefs does not document this process very well
or it does not work the way I understand the description there...

>How-To-Repeat:

# mount
root_device on / type ffs (read-only, local)
# tunefs -N wd0a
tunefs: tuning /dev/rwd0a
tunefs: current settings of /dev/rwd0a
        maximum contiguous block count 4
        maximum blocks per file in a cylinder group 2048
        minimum percentage of free space 5%
        optimization preference: time
        average file size: 16384
        expected number of files per directory: 64
        journal log file location: in filesystem
        journal log file size: 64MB (67108864 bytes)
        journal log flags:
        quotas disabled
        POSIX.1e ACLs disabled
        NFS4 ACLs disabled
tunefs: no changes made
# tunefs -l 0 wd0a
tunefs: tuning /dev/rwd0a
tunefs: log file size cleared from 67108864
# tunefs -N wd0a
tunefs: tuning /dev/rwd0a
tunefs: current settings of /dev/rwd0a
        maximum contiguous block count 4
        maximum blocks per file in a cylinder group 2048
        minimum percentage of free space 5%
        optimization preference: time
        average file size: 16384
        expected number of files per directory: 64
        journal log file location: in filesystem
        journal log file size: 64MB (67108864 bytes)
        journal log flags: clear-log
        quotas disabled
        POSIX.1e ACLs disabled
        NFS4 ACLs disabled
tunefs: no changes made
# mount /
# mount
/dev/wd0a on / type ffs (local)
# tunefs -N wd0a
tunefs: tuning /dev/rwd0a
tunefs: current settings of /dev/rwd0a
        maximum contiguous block count 4
        maximum blocks per file in a cylinder group 2048
        minimum percentage of free space 5%
        optimization preference: time
        average file size: 16384
        expected number of files per directory: 64
        journal log file location: in filesystem
        journal log file size: 64MB (67108864 bytes)
        journal log flags:
        quotas disabled
        POSIX.1e ACLs disabled
        NFS4 ACLs disabled
tunefs: no changes made



I expected the "journal log" lines to completely go away, like in this
output for another filesystem that does not have any log:

tunefs: tuning /dev/rdk0
tunefs: current settings of /dev/rdk0
        maximum contiguous block count 2
        maximum blocks per file in a cylinder group 4096
        minimum percentage of free space 5%
        optimization preference: time
        average file size: 16384
        expected number of files per directory: 64
        quotas disabled
        POSIX.1e ACLs disabled
        NFS4 ACLs disabled
tunefs: no changes made


>Fix:
n/a